1. Field of the Invention
The present invention concerns a vibration canceler for a shaft rotating about an axis. The vibration canceler includes an inertial ring which is fastened to the shaft in a relatively untwistable manner by at least one elastic ring made of a rubber-like material.
2. Description of the Prior Art
A vibration canceler is shown in DE-PS 588 245. The elastic ring in the vibration canceler shown in that publication is fastened to a hub ring and joined by this hub ring to the shaft. This arrangement increases the cost of manufacturing such a rotational vibration canceler and makes it more difficult to assemble the vibration canceler.
The underlying object of the present invention is to provide a vibration canceler for a shaft rotating about an axis which can be manufactured and assembled in a simple manner.
In the vibration canceler according to the present invention, the elastic ring contacts the outer circumference of the shaft by direct abutment and is untwistably pressed on to the shaft by the inertial ring. The relative displacements of the inertial ring which occur during normal use are due exclusively to elastic deformation of the elastic ring itself. The surfaces bounding the elastic ring on both the inside and the outside contact, in a fully immovable manner, the contacting surfaces of the shaft on one side and the inertial ring on the other side. By eliminating the hub ring, manufacture and assembly of the vibration canceler according to the present invention are much simpler than in previously known vibration cancelers. Nonetheless, features equivalent to known vibration cancelers are obtained.
The elastic ring can be provided with a split at one or more circumferential location, which simplifies assembly in applications where the shaft to be equipped has enlargements on both ends, which enlargements have an outer diameter greater than the inner diameter of the elastic ring. The inertial ring can be slid over the enlargement of the shaft onto the preinstalled elastic ring. Immovable pressing of the elastic ring on to the outer circumference of the shaft arises as a result. It is also possible to use a divided inertial ring which is slid on to the preinstalled elastic ring in a direction transverse to the shaft and fastened thereupon by joining together the segments which form the inertial ring. The elastic ring as well as the inertial ring can consist of more than two partial segments if need be.
According to an advantageous embodiment, the elastic ring is bonded to the shaft and/or the inertial ring. In such an embodiment, it is no longer necessary to use a very large contact pressure to obtain an immovable contact. Such a variant is very advantageous in particular with regard to the reduction of vibrations at a comparatively low frequency.
A particularly secure anchoring can be achieved in the vibration canceler according to the present invention if the elastic ring, the shaft and/or the inertial ring are provided at one or more locations in the region of the mutually contacting surfaces with a mutually engaging, relief-like surface structuring. The usage of a secondary adhesive is frequently unnecessary in such an embodiment. Nonetheless, proper fastening is achieved while avoiding high contact pressure.
A method for manufacturing the vibration canceler according to the invention in which, in succession, the elastic ring is fastened to the shaft and the inertial ring is then fastened to the elastic ring, for example, in the course of successively mounting in their final position the hollow cylindrical parts which make up the elastic ring and the inertial ring, has proven particularly advantageous. A lubricant can be used if necessary. The reverse order of assembly can naturally be used as well and is recommended as more advantageous under certain circumstances.
In a method for manufacturing the vibration canceler in which the elastic ring is bonded to the shaft and/or the inertial ring, it has proven advantageous if an adhesive in micro-encapsulated form is used for bonding purposes and is applied to the surface zones to be bonded before the individual parts are assembled. The micro-capsules containing the adhesive are dry on the outside such that a bonding procedure can be performed in a very clean manner. The mutual pressure which arises when the surfaces to be bonded are brought together results in the destruction of the micro-capsules so that the adhesive contained therein is activated. This takes place directly between the surfaces to be bonded and produces a solid, mutual bond between them.